A one stringer separable fastener, such as that disclosed in U.S. Pat. No. 2,784,473, has a single folded stringer with upper and lower sliders mounted thereon. The lower slider is stopped at a lower position by an enlargement on a bar member on one end of the single stringer to thus serve as a box or retainer member on the bottom of the slide fastener. A pin member is mounted on the other end of the single stringer for insertion through the upper and lower sliders to form a separable slide fastener. The upper end of the fastener is defined by the fold.
In another prior art one stringer separable fastener, it has been proposed to form the pin member by severing the head portions of the coupling elements and securing a thermoplastic tape on both sides of the stringer tape so that the thermoplastic tape extends around the remaining portions of the coupling elements to thus form a pin member. This particular one stringer separable fastener has been proposed for incorporation in a sleeping bag.
Examples of the employment of slide fasteners in sleeping bag arrangements are found in U.S. Pat. No. 3,510,889 and No. 3,639,931.
The prior art also contains many apparatuses for gapping or removing the coupling elements from the tapes of slide fasteners in a continuous stringer or pair of stringers of the slide fastener. One such apparatus, as illustrated in U.S. Pat. No. 4,019,240, utilizes a variable distance from a sensor to the gapping mechanism to determine the length of chain between gaps, i.e., the sensor senses the previous gap to stop the pulling of the slide fastener chain through the gapping station and to initiate a subsequent gapping cycle. In another prior art arrangement, a counting circuit operated by a pulse generator on a shaft driving a slide fastener chain pulling wheel is utilized to measure the length of slide fastener chain between operations of the gapping apparatus.
The prior art further contains methods and apparatus where multiple operations are performed on a slide fastener chain at different stations, for example, U.S. Pat. No. 2,885,774, No. 3,263,238, No. 3,570,104 and No. 3,765,348. However, these methods and apparatus have one or more deficiencies such as being unduly complex or expensive, being relatively slow due to the need for precise positioning of the slide fastener chain at various stations, being too large, etc.